Automatic starting mechanism for motor vehicle engines



E. A. WATSON Jan. 22, 1935.

AUTOMATIC STARTING MECHANISM FOR MOTOR VEHICLE ENGINES Filed June 50, 1933 KJUUUU Mme I Patented Jan. 22, 1935 PATENT OFFICE AUTOMATIC STARTING MECHANISM FOR MOTOR v VEHICLE ENGINES Ernest Ansley Watson, Birmingham, England Application June. so, 1933, Serial No. 678,445 In Great Britain July 9, 1932 Claims.

This invention relates to automatic starting mechanism for motor vehicle engines. Ordinarily the control of such mechanism is made de-- pendent upon a dynamo driven by the engine.

5, When the dynamo is at rest an electro-magnetic switch in a circuit which controls the starter circuit is held closed by a spring, so that initial starting of the engine can be effected at any time by the closing of the usual hand switch. After the closing of the hand switch, and when the dynamo is rotating at a suflicient speed, current is supplied by the dynamo to the winding of the electro-magnetic switch for the purpose of opening it and holding it open to prevent recurrent operation of the starting motor. Ordinarily the electro-magnet of the switch above-mentioned is designed to withstand without injury the full voltage which can be imposed upon it by the dynamo, and on this account its response to the lower voltages generated when the dynamo is running slowly is unreliable, with the result that it is possible for the starting mechanism to come into action while the engine is running. The object of the present invention, which relates to mechanism of the kind above described, is to provide means whereby the electro-magnetic switch is capable of being operated reliably by low voltages and is at the same time safeguarded against excessive current when the dynamo is operating at full speed.

The invention comprises the combination with the electro-magnetic switch, of a resistance arranged in series with the winding of that switch, and an electro-magnetically operated cut-out device which serves both to put the resistance into and out of action and also to connect the dynamo to the usual battery, the arrangement being such that at normal speeds, when the dynamo is connected to the battery, the resistance is in series with the winding of the switch, whilst at low speeds, when the dynamo is disconnected from the battery, the resistance is short circuited, allowing current to flow directly to the switch winding and causing the switch to be held open until the engine stops or nearly stops.

The single figure of the accompanying diagram illustrates one mode of carrying the invention into eilfect.

Referring to the diagram, the system illustrated is one which includes the usual cut-out device a situated between the dynamo b and the battery 0. This device is adapted to interconnect the dynamo and battery when the dynamo generates sufllcient voltage. The movable part of the cut-out device, which is provided with a contact co-operating with a contact connected to the battery, is also provided with an additional contact which can co-operate with a contact in the circuit containing the electro-magnet of the switch aforesaid, (this switch being indicated in the diagram by the part marked d), and between this contact and the dynamo is arranged a resistance e. When the dynamo is rotating slowly and is not generating sufiicient voltage to operate the cut-out device a, the movable part of the cut-out device bears under the action of a spring against the contact connected to the resistance and thereby short circuits the resistance, allowing current to flow directly from the dynamo to the winding of the switch at d. This winding is so designed that a small current, such as might be developed by the slow rotation of the armature of the dynamo in the residual magnetic field of the dynamo, is sufiicient to keep the switch open in a reliable manner. Such a winding would, however, be incapable of withstanding a heavy current corresponding to the full working voltage of the dynamo.

When the dynamo operates at normal speed and is connected to the battery by the cut-out a the movable part of the cut-out is separated from the resistance contact, causing the resistance e to be put into series with the winding of the switch at d and thereby preventing excessive current flowing to that winding from the dynamo.

In the example illustrated the cut-out a is actuated by the usual voltage coil f, and is held connected to the battery contact by the usual series coil 9. The winding h is the field winding of the dynamo.

By this invention we are able to ensure in a simple and reliable manner the holding open of the automatic starting switch even when the engine is rotating slowly, and so prevent the undesirable risk of operation of the starting motor while the engine is running, owing to accidental closing of the automatic switch.

What I claim is:

1. In an electrical system for internal combustion engines an engine driven generator, starting mechanism for the engine including a battery and starting motor, means for controlling said starting mechanism including a lockout device responsive to the voltage of the generator for preventing actuation of the starting mechanism during self-operation of the engine, and means controlled by the voltage of the generator for automatically reducing the sensitivity of said lockout device.

2. In an electrical system for internal combustion engines an engine driven generator, starting mechanism for the engine including a battery and starting motor, and a magnetic starting switch, a relay for controlling said magnetic starting switch including a coil energized by said generator to maintain the starting switch open, a protective resistance element, and generator voltage controlled means for connecting said resistance element in series with said coil.

3. An electrical system for internal combustion engines including a battery, an engine driven generator for charging the battery and a starting system, means under the control of the operator for energizing said starting system to start the engine, means energized by said generator for preventing energization of the starting system while the engine is self-operative, and means responsive tothe voltage of said generator for protecting said preventing means by reducing the voltage applied thereto when the generating voltage reaches a charging value.

4. An electrical system for internal combustion engines including a battery, an engine driven generator for charging the battery and a starting systemincluding a starting motor and. a magnetic starting switch, means under the control of the operator for energizing said starting switch to start the engine, a relay including a coil energized by said generator for preventing energization of the starting switch while the engine is 5 self-operative, and means responsive to a predetermined rise in the voltage of said generator for protecting said relay coil from the full voltage of the generator.

5. An electrical system for internal combustion engines including a battery, an engine driven generator for charging the battery, a reverse current relay for controlling the connection of the generator to the battery, a starting system for the engine including a magnetic starting switch, means for automatically energizing the starting switch in case of engine stall, means including a relay having a coil energized from the generator for preventing energization of the starting switch during self-operation of the engine, a resistance element in series with said coil, and means operated by said reverse current relay for short circuiting said resistance element when the generator voltage is below the charging value.

ERNEST ANSLEY WATSON. 

